Genwen Lin

Degradation behavior of foamed nickel positive electrodes of Ni–MH batteries

The extrusion mechanism has been demonstrated to be the major cause for the capacity decay of the positive electrodes during cycling. However, based on our SEM and EPMA observations on cycled electrodes we found that some active material on the foamed nickel electrodes came off into scales especially as the electrodes cycled at 1C rate of discharge. This phenomena is suggested as another important cause for the capacity decay of positive electrodes and may be explained by the internal stress induced by the different volume change at the outer layer and the core due to phase and structure transformation during cycling.

The maximum solid solubility of the transition metals in palladium

Abstract The maximum solid solubility limit ( C max ) of transition metals dissolved in palladium can be described as an equation in semi-empirical theories with parameters such as electronegativity difference, atomic diameter and covalent electrons. It has been found that the electronegativity difference and the covalent electron number mainly affected the C max of transition metals in palladium. The atomic size parameter had the smallest effect on the C max .